private DERSequence encodeDataSequence( ChangePasswordData data )
{
DERSequence sequence = new DERSequence();
sequence.add( new DERTaggedObject( 0, new DEROctetString( data.getPassword() ) ) );
// OPTIONAL
if ( data.getPrincipalName() != null )
{
sequence.add( new DERTaggedObject( 1, PrincipalNameEncoder.encode( data.getPrincipalName() ) ) );